Abstract
A stabilizer-free weak Galerkin (SFWG) finite element method was introduced and analyzed in Ye and Zhang (SIAM J. Numer. Anal. 58: 2572–2588, 2020) for the biharmonic equation, which has an ultra simple finite element formulation. This work is a continuation of our investigation of the SFWG method for the biharmonic equation. The new SFWG method is highly accurate with a convergence rate of four orders higher than the optimal order of convergence in both the energy norm and the \(L^2\) norm on triangular grids. This new method also keeps the formulation that is symmetric, positive definite, and stabilizer-free. Four-order superconvergence error estimates are proved for the corresponding SFWG finite element solutions in a discrete \(H^2\) norm. Superconvergence of four orders in the \(L^2\) norm is also derived for \(k\geqslant 3\), where k is the degree of the approximation polynomial. The postprocessing is proved to lift a \(P_k\) SFWG solution to a \(P_{k+4}\) solution elementwise which converges at the optimal order. Numerical examples are tested to verify the theories.
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References
Al-Taweel, A., Wang, X.: A note on the optimal degree of the weak gradient of the stabilizer-free weak Galerkin finite element method. Appl. Numer. Math. 150, 444–451 (2020)
Chai, S., Zou, Y., Zhou, C., Zhao, W.: Weak Galerkin finite element methods for a fourth order parabolic equation. Numer. Methods PDE 35, 1745–1755 (2019)
Chen, G., Feng, M.: A \(C^0\)-weak Galerkin finite element method for fourth-order elliptic problems. Numer. Methods PDE 32, 1090–1104 (2016)
Mu, L., Wang, J., Ye, X.: A weak Galerkin finite element method for biharmonic equations on polytopal meshes. Numer. Methods PDE 30, 1003–1029 (2014)
Mu, L., Wang, J., Ye, X., Zhang, S.: A \(C^0\) Weak Galerkin finite element methods for the biharmonic equation. J. Sci. Comput. 59, 437–495 (2014)
Mu, L., Ye, X., Zhang, S.: Development of a P2 element with optimal L2 convergence for biharmonic equation. Numer. Methods PDE 35, 1497–1508 (2019)
Wang, C., Wang, J.: An efficient numerical scheme for the biharmonic equation by weak Galerkin finite element methods on polygonal or polyhedral meshes. Comput. Math. Appl. 68, 2314–2330 (2014)
Wang, J., Ye, X.: A weak Galerkin finite element method for second-order elliptic problems. J. Comput. Appl. Math. 241, 103–115 (2013). arXiv:1104.2897v1
Wang, J., Ye, X.: A weak Galerkin mixed finite element method for second-order elliptic problems. Math. Comput. 83, 2101–2126 (2014). arXiv:1202.3655v1
Ye, X., Zhang, S.: A stabilizer-free weak Galerkin finite element method on polytopal meshes. J. Comput. Appl. Math. 371, 112699 (2019). arXiv:1906.06634
Ye, X., Zhang, S.: A stabilizer free weak Galerkin method for the biharmonic equation on polytopal meshes. SIAM J. Numer. Anal. 58, 2572–2588 (2020). arXiv:1907.09413
Ye, X., Zhang, S.: A family of H-div-div mixed triangular finite elements for the biharmonic equation. (2021) Preprint. https://drive.google.com/file/d/14Rx9auM4D_bOpo4gTIff4z6l2XtJVRfK
Ye, X., Zhang, S., Zhang, Z.: A new P1 weak Galerkin method for the biharmonic equation. J. Comput. Appl. Math. 365, 112337 (2020). https://doi.org/10.1016/j.cam.2019.07.002
Zhai, Q., Xie, H., Zhang, R., Zhang, Z.: The weak Galerkin method for elliptic eigenvalue problems. Commun. Comput. Phys. 26, 160–191 (2019)
Zhang, R., Zhai, Q.: A weak Galerkin finite element scheme for the biharmonic equations by using polynomials of reduced order. J. Sci. Comput. 64, 559–585 (2015)
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Ye, X., Zhang, S. Four-Order Superconvergent Weak Galerkin Methods for the Biharmonic Equation on Triangular Meshes. Commun. Appl. Math. Comput. 5, 1323–1338 (2023). https://doi.org/10.1007/s42967-022-00201-5
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DOI: https://doi.org/10.1007/s42967-022-00201-5